Method and system for distributing messages from a signal transfer point to a plurality of service control points

ABSTRACT

A signal transfer point distributes a plurality of messages to a plurality of service control points in accordance with a distribution plan. The distribution plan includes each of the service control points. Each of the plurality of messages from the signal transfer point is distributed to a corresponding one of the plurality of service control points in accordance with the distribution plan.

This application is a continuation of U.S. application Ser. No.08/804,102, filled Feb. 20, 1997 now U.S. Pat. No. 5,878,129, issuedMar. 2, 1999, which is hereby incorporated by reference herein.

TECHNICAL FIELD

The present invention relates to methods and systems for communicatingmessages from a signal transfer point to a plurality of service controlpoints in a telecommunication system.

BACKGROUND OF THE INVENTION

The Advanced Intelligent Network (AIN) and Intelligent Network (IN)architectures utilize a centrally-located service control point (SCP) tocontrol services on service switching points (SSPs) at local telephoneexchanges. Each SSP is capable of implementing a set of functionalcomponents for defining one or more telecommunication services. Thefunctional components can include providing a dial tone, collectingdigits, and performing number translations for example. Each SCPincludes a processor and a database used to direct the SSPs to perform asequence of functions to provide a desired service. As a result, callcontrol of AIN/IN services is carried out by the centralized SCP ratherthan at each local exchange.

To afford a complete back-up/fail-safe configuration if an SCP were tofail, SCPs are configured in mated pairs. Typically, each of the SCPs ina mated pair is utilized at 40% occupancy during a peak usage period sothat if one SCP were to fail, the other SCP would have the capacity tohandle the full load of calls. Here, the functioning SCP would have anoccupancy of 80%, which provides a 20% degree of safety for anunexpectedly-high load during the peak usage period.

A shortcoming of this architecture is in the expense of operating matedpairs of functioning SCPs well below their full capacity, typically,each having an occupancy less than or equal to 40%.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is pointed out with particularity in the appended claims.However, other features of the invention will be best understood byreferring to the following detailed description in conjunction with theaccompanying drawings in which:

FIG. 1 is a block diagram of an architecture of a portion of atelecommunication system in accordance with the present invention;

FIG. 2 is a flow chart of an embodiment of a method of distributing aplurality of messages from a signal transfer point to a plurality ofservice control points in a telecommunication system;

FIG. 3 is a flow chart of an embodiment of a method of distributing eachof a plurality of messages from a signal transfer point to acorresponding one of a plurality of service control points in accordancewith a sequential distribution plan;

FIG. 4 is a flow chart of an embodiment of a method of distributing eachof a plurality of messages from a signal transfer point to acorresponding one of a plurality of service control points in accordancewith a weighted, sequential distribution plan; and

FIG. 5 is a flow chart of an embodiment of a method of distributing eachof a plurality of messages from a signal transfer point to acorresponding one of a plurality of service control points in accordancewith a weighted distribution plan.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Embodiments of the present invention distribute messages among a clusterof service control points in accordance with a distribution plan.Advantageously, a fuller utilization of service control point resourcesis realized in comparison to a mated pair configuration. Additionally,quality of service is not compromised should one of the service controlpoints fail.

FIG. 1 is a block diagram of an architecture of a portion of atelecommunication system in accordance with the present invention. Thetelecommunication system includes a plurality of service control points10, a plurality of signal transfer points 12, and a plurality of serviceswitching points 14.

The service switching points 14 intercept calls which require specialhandling to provide any of a variety of AIN/IN services associated withthe call. The service switching points 14 detect an AIN/IN call byrecognizing a trigger associated therewith. For these calls, the serviceswitching points 14 send corresponding query messages to the servicecontrol points 10 to obtain call handling information to complete eachcall. Typically, the service switching points 14 are located at centraloffices, end offices or tandem offices of a public telephone system.

The query messages are communicated from the service switching points 14to the service control points 10 via the signal transfer points 12.Typically, the signal transfer points 12 are deployed ingeographically-separated pairs so that in the event of a disaster at onesite, the service switching points 14 can communicate with the servicecontrol points 10 via a signal transfer point at another site.

The plurality of service control points 10 provide call handlinginformation in response to the query messages generated by the serviceswitching points 14. Each of the service control points 10 includes adatabase containing service-specific logic and data for forming aresponse message containing the call handling information. Responsemessages containing the call handling information are communicated backto the service switching points 14 via the signal transfer points 12.Each response message instructs a service switching point on how toproceed with a respective AIN/IN call.

Under this architecture, the service control points 10 are organized asa cluster to provide control for calls served by the service switchingpoints 14. The signal transfer points 12 are utilized to distribute theaggregate load of call messages generated by the service switchingpoints 14 over the service control points 10 in the cluster. For maximumflexibility in distributing the calls, it is preferred that each of thesignal transfer points 12 be linked to all of the service control points10.

Each of the signal transfer points 12 distributes each of a plurality ofmessages to a corresponding one of the plurality of service controlpoints 10 in accordance with a predetermined distribution plan. Variousdistribution plans, including those specifically described herein, canbe utilized to distribute the messages to the service control points 10.

A weighted distribution process allows each service transfer point todistribute query messages based on a weighting factor established foreach service control point in the cluster. This process can beaccomplished by an algorithm that either counts the number of queriesbeing sent to a specific service control point or maintains a percentageof calls/messages being offered per service control point.

A sequential distribution process sets the service control points 10 ina hierarchy using a list of the service control points 10. Using thelist, the service control points 10 are sequentially selected throughthe cluster for receiving a query message. When the last service controlpoint in the list is reached, the list is recycled from the beginning.

Preferably, the distribution plan utilized to distribute the querymessages can be modified through data changes at a translations locationin an administration center. These translations can change the datarelating to specific service control points utilized in a distributionalgorithm and/or change the distribution algorithm itself. For example,with the sequential distribution process, the administrator is capableof changing the sequence order, the start of the sequence, and the endof the sequence.

It is also preferred that a plurality of predetermined distributionplans are available from which an administrator can select adistribution plan. Here, each distribution plan can be assigned a plannumber and/or a plan name. Each distribution plan contains the datarequired to identify and select specific service control points. As aresult, when the need arises for changing the distribution plan, theadministrator can simply activate a predetermined distribution planrather than having to build a new distribution plan. For example, theplurality of predetermined distribution plans can include a plurality ofdifferent sequences for use in a sequential distribution process.Preferably, the selection process is table-driven for ease oftranslations input and administration.

Typically, each of the signal transfer points 12 utilizes the samedistribution plan for distributing messages among the service controlpoints 10. It is noted, however, that different distribution plans canbe simultaneously utilized by the signal transfer points 12 if desiredfor different clusters.

The selection of the service control points 10 to form the cluster canbe made with regard to any of a variety of criteria, including but notlimited to, specific services which are to be provided, geographicneeds, regulatory requirements, and functional capability. Preferably,the cluster is designed so that total occupancy of any one of theservice control points 10 does not exceed the excess occupancy capacityof the remaining service control points. As a result, should any one ofthe service control points 10 fail, the remaining service control pointshave the capacity to pick up the excess load of query messages.

For purposes of illustration, four service control points 20, 22, 24,and 26 are illustrated in the cluster. It is noted, however, that thecluster of service control points 10 generally can include any number ofservice control points. Further, although the portion of thetelecommunication system in FIG. 1 is illustrated to include two serviceswitching points 34 and 36, and two signal transfer points 30 and 32, itis noted that any number of service switching points and signal transferpoints can be included. Still further, it is noted that a larger portionof the telecommunication system than that illustrated in FIG. 1 wouldinclude a plurality of clusters of service control points, wherein eachcluster provides operating control for a respective plurality of serviceswitching points.

The service control points 10 in the cluster can be deployed at a singlesite or at a number of different sites. For example, the service controlpoints 20, 22, 24, and 26 can all be located at a single site. Inanother example, the service control points 20 and 22 are located at onesite, while the service control points 24 and 26 are located at anothersite. In a further example, the service control point 20 is located at afirst site, the service control point 22 is located at a second site,the service control point 24 is located at a third site, and the servicecontrol point 26 is located at a fourth site.

The signal transfer points 12 are responsible for recognizing when aservice control point is malfunctioning, and for taking correctiveaction in response thereto. For example, the signal transfer points 12can be notified by a service control point when a subsystem has failed.In response to recognizing the malfunctioning, each of the signaltransfer points 12 can utilize a modified distribution plan which eitheromits the malfunctioning service control point or reduces the share ofmessages distributed thereto.

It is preferred that the administration center allow a service controlpoint to be manually taken out of service in a manner which appears asthough the service control point has failed. This can be utilized inconditions where a maintenance group wants to take aninfrequently-failing service control point out of service. The manualintervention takes on the characteristics of a true failure of theservice control point, and hence, the distribution process isautomatically modified as preprogrammed per the active distributionplan.

It is further preferred that all changes to the active distribution planbe logged for the purpose of security, maintenance, and analysis. Thesechanges include, but are not limited to, provisioning or translationchanges, failure conditions, and maintenance changes.

Further, an alarm indicator can be included should the distributionprocess be changed because of failure of a service control point. Thealarm indicator is capable of recognizing more than one failure in acluster, and escalating the alarm condition in response thereto.

FIG. 2 is a flow chart of an embodiment of a method of distributing aplurality of messages from a signal transfer point to a plurality ofservice control points in a telecommunication system. The method can beutilized by each of the signal transfer points 12 illustrated in FIG. 1to distribute messages to the service control points 10 in apredetermined cluster.

As indicated by block 40, the method includes a step of selecting adistribution plan for distributing the plurality of messages among theplurality of service control points. Preferably, the distribution planis selected from a plurality of predetermined distribution plans.Examples of distribution plans include a sequential selection plan and aweighted selection plan.

In a sequential selection plan, the distribution plan includes adistribution sequence for distributing messages among the servicecontrol points. Typically, each of the plurality of service controlpoints is included at least once in the distribution sequence. An equalloading can be produced for each of the service control points byincluding each of the service control points once and only once in thedistribution plan.

In one embodiment of a weighted selection plan, the above-describedsequential distribution plan is augmented to include a respective countfor each service control point. Here, the respective count of messagesis distributed to a service control point before proceeding to asubsequent service control point in the distribution sequence to whichmessages are distributed.

In another embodiment of a weighted selection plan, the distributionplan includes a respective distribution proportion for each of theservice control points. Here, each of the service control points has aproportion of the plurality of messages distributed thereto based uponits respective distribution proportion. The plurality of messages can bedistributed either deterministically or stochastically to produce eachrespective distribution proportion.

As indicated by block 42, the method includes a step of distributingeach of the plurality of messages from the signal transfer point to acorresponding one of the plurality of service control points inaccordance with the distribution plan. Implementations for performingthis step are subsequently described with reference to FIGS. 3 to 5.

As indicated by block 44, the method includes a step of determining thata service control point is malfunctioning. It is noted that the term"malfunction" should be construed to include any degree of loss offunction, up to and including a complete loss of function.

The signal transfer point can determine that the service control pointis malfunctioning based upon a message received from the service controlpoint. The service control point can be adapted to indicate the severityof its condition in the message. For example, various degrees ofseverity, from a cautionary message that the service control point is"in trouble" to an alarm message which requests that no messages bedistributed to the service control point, can be indicated by themessage.

Alternatively, the signal transfer point can determine that the servicecontrol point is malfunctioning based upon a duration betweentransferring a query message thereto and receiving a response messagetherefrom. If the duration exceeds a predetermined threshold, the signaltransfer point can conclude that the service control point ismalfunctioning. It is noted that the signal transfer point can detect amalfunctioning service control point when the predetermined threshold isexceeded before receiving a response message.

As indicated by block 46, the method includes a step of utilizing amodified distribution plan for distributing subsequent messages to theservice control points once it has been determined that one of theservice control points is malfunctioning. Here, for example, themodified distribution plan can exclude the malfunctioning servicecontrol point from a distribution sequence included in the distributionplan. As another example, the distribution proportion for themalfunctioning service control point can be reduced, or set to zero, inthe modified distribution plan. In turn, the distribution proportion foreach of the remaining service control points can be modified to handlethe excess load of messages.

FIG. 3 is a flow chart of an embodiment of a method of distributing eachof a plurality of messages from a signal transfer point to acorresponding one of a plurality of service control points in accordancewith a sequential distribution plan. The sequential distribution planincludes a distribution sequence which dictates the order in whichmessages are distributed to the service control points.

As indicated by block 50, the method includes a step of receiving amessage from a service switching point. Typically, the message includesa query message which is to be transferred to a service control pointfor the purpose of obtaining call handling information in a responsemessage. It is noted that the message can be received either directlyfrom the service switching point or from a queue of messages receivedfrom the service switching point.

As indicated by block 52, the method includes a step of distributing themessage to a service control point indicated by a current position inthe distribution sequence. Thereafter, a step of updating the currentposition to a subsequent position in the distribution sequence isperformed, as indicated by block 54.

The current position can be updated by incrementing or decrementing itsposition within the distribution sequence. After completing the entiredistribution sequence, the current position is returned to an initialposition so that the distribution sequence can be cycled to distributesubsequent messages.

Flow of the routine is directed back to block 50, at which time asubsequent message is received and to block 52, wherein the subsequentmessage is distributed to a service control point indicated by theupdated position within the distribution sequence. Hence, the stepsindicated by blocks 50, 52, and 54 are repeated to distribute theplurality of messages in accordance with the sequential distributionplan.

Table I shows an example of a sequential distribution plan for theportion of the telecommunication system illustrated in FIG. 1. In thisexample, messages received by a signal transfer point are routed to theservice control points 10 in the following order: a first message isrouted to the service control point 20; a second message is routed tothe service control point 24; a third message is routed to the servicecontrol point 22; and a fourth message is routed to the service controlpoint 26. The distribution sequence is cycled for subsequent messages;in particular, a fifth message is routed to the service control point20, a sixth message is routed to the service control point 24, a seventhmessage is routed to the service control point 22, and an eighth messageis routed to the service control point 26.

As a result, each of the service control points 10 handle a 25% share ofthe message load. The capacity of the service control points 10 is suchthat each has an occupancy of approximately 60% during a peak usageperiod. In general, a sequential distribution plan is well-suited fordistributing messages among a cluster of service control points whichhave equal capacities.

                  TABLE I                                                         ______________________________________                                        SEQUENCE     SHARE OF LOAD                                                                              OCCUPANCY                                           ______________________________________                                        SCP1         1/4          60%                                                 SCP3         1/4          60%                                                 SCP2         1/4          60%                                                 SCP4         1/4          60%                                                 ______________________________________                                    

Table II shows an example of a modified distribution plan when the oneof the service control points is determined to be malfunctioning. Forthe purpose of illustration, the service control point 24 is consideredto be malfunctioning in this example.

                  TABLE II                                                        ______________________________________                                        SEQUENCE     SHARE OF LOAD                                                                              OCCUPANCY                                           ______________________________________                                        SCP1         1/3          80%                                                 SCP3         --           --                                                  SCP2         1/3          80%                                                 SCP4         1/3          80%                                                 ______________________________________                                    

Messages received by the signal transfer point are routed to the servicecontrol points 10 as follows: a first message is routed to the servicecontrol point 20; a second message is routed to the service controlpoint 22; and a third message is routed to the service control point 26.The distribution sequence is cycled for subsequent messages; inparticular, a fourth message is routed to the service control point 20,a fifth message is routed to the service control point 24, and a sixthmessage is routed to the service control point 22.

Using the modified distribution sequence, each of the functioningservice control points 20, 24, and 26 handles one third of the messageload when one of the service control points is malfunctioning. Further,the occupancy of each of the functioning service control points 20, 24,and 26 increases to approximately 80% during the peak usage period.

FIG. 4 is a flow chart of an embodiment of a method of distributing eachof a plurality of messages from a signal transfer point to acorresponding one of a plurality of service control points in accordancewith a weighted, sequential distribution plan. The weighted, sequentialdistribution plan includes a distribution sequence which dictates theorder in which messages are distributed to the service control points,and a respective number of messages associated with each service controlpoint in the distribution sequence.

As indicated by block 60, the method includes a step of receiving amessage from a service switching point. As mentioned earlier, themessage typically includes a query message which is to be transferred toa service control point for the purpose of obtaining call handlinginformation in a response message. The message can be received eitherdirectly from the service switching point or from a queue of messagesreceived from the service switching point.

As indicated by block 62, the method includes a step of distributing themessage to a service control point indicated by a current position inthe distribution sequence. A step of updating a count associated withthe service control point is performed as indicated by block 64. Thecount is updated to reflect that the message has been distributed to theservice control point. Preferably, the count is indicative of how manymessages are received for a particular application (subsystem) at theservice control point. A table of counts can be maintained for eachapplication or subsystem over the plurality of service control points.

As indicated by block 66, the method includes a step of determiningwhether the count has attained the predetermined number of messages forthe service control point as dictated by the distribution plan. If so, astep of resetting the count, as indicated by block 68, and a step ofupdating the current position to a subsequent position in thedistribution sequence, as indicated by block 70, are performed. Thecurrent position can be updated by incrementing or decrementing itsposition within the distribution sequence. After completing the entiredistribution sequence, the current position is returned to an initialposition so that the distribution sequence can be cycled to distributesubsequent messages.

If, in block 66, the count has not attained the predetermined number ofmessages for the service control point as dictated by the distributionplan, flow of the routine is directed by to block 60. Similarly, afterupdating the current position in block 70, flow of the routine isdirected back to block 60. The above-described steps are then repeatedto distribute the plurality of messages in accordance with the weighted,sequential distribution plan.

Table III shows an example of a weighted, sequential distribution planfor the portion of the telecommunication system illustrated in FIG. 1.In this example, messages received by a signal transfer point are routedto the service control points 10 in the following order: seven messagesare routed to the service control point 22; three messages are routed tothe service control point 20; seven messages are routed to the servicecontrol point 24; and three messages are routed to the service controlpoint 26. The distribution sequence is cycled for subsequent messages;in particular, seven messages are routed to the service control point22, three messages are routed to the service control point 20, sevenmessages are routed to the service control point 24, and three messagesare routed to the service control point 26.

In another preferred approach, messages are initially distributed usingthe sequence given in Table III. In other words, a first message isrouted to the service control point 22, a second message is routed tothe service control point 20, a third message is routed to the servicecontrol point 24, and a fourth message is routed to the service controlpoint 26. For each of the service control points, a count of the numberof messages distributed thereto is maintained. For example, after goingthrough the sequence once, each service control point has a count ofone.

The step of routing messages using the sequence is repeated until acount for a service control point has attained its associated countgiven in Table III. For example, a fifth message is routed to theservice control point 22, a sixth message is routed to the servicecontrol point 20, a seventh message is routed to the service controlpoint 24, an eighth message is routed to the service control point 26, aninth message is routed to the service control point 22, a tenth messageis routed to the service control point 20, an eleventh message is routedto the service control point 24, and a twelfth message is routed to theservice control point 26. At this time, the count associated with theservice control point 20 is three and the count associated with theservice control point 26 is three.

Thereafter, subsequent messages are routed wherein the service controlpoints 20 and 26 are excluded from the sequence. For example, athirteenth message is routed to the service control point 22, afourteenth message is routed to the service control point 24, afifteenth message is routed to the service control point 22, a sixteenthmessage is routed to the service control point 24, a seventeenth messageis routed to the service control point 22, an eighteenth message isrouted to the service control point 24, a nineteenth message is routedto the service control point 22, and a twentieth message is routed tothe service control point 24. At this time, the count associated withthe service control point 22 is seven and the count associated with theservice control point 24 is seven.

Thereafter, the counts associated with the service control points areinitialized back to zero, and the process is repeated for subsequentmessages.

                  TABLE III                                                       ______________________________________                                        SEQUENCE COUNT     SHARE OF LOAD OCCUPANCY                                    ______________________________________                                        SCP2     7         35%           47%                                          SCP1     3         15%           60%                                          SCP3     7         35%           47%                                          SCP4     3         15%           60%                                          ______________________________________                                    

Using either approach, the service control points 22 and 24 each handlea 35% share of the message load, while the service control points 20 and26 each handle a 15% share. The capacity of the service control points10 is such that two have an occupancy of approximately 60% and the othertwo have an occupancy of approximately 47% during a peak usage period.

In general, a weighted, sequential distribution plan is well-suited fordistributing messages among a cluster of service control points whichhave unequal capacities. For example, the above-described distributionplan is suited for service control points 22 and 24 which are capable ofhandling 300 transactions per second, and service control points 20 and26 which are capable of handling 100 transactions per second.

When a service control point is determined to be malfunctioning, itsrespective count can be modified in a weighted, sequential distributionplan. The count can be reduced to a level commensurate with the severityof the condition of the service control point. For a catastrophicfailure of the service control point, the count can be set to zero, oralternatively, the service control point can be removed from thesequence.

FIG. 5 is a flow chart of an embodiment of a method of distributing eachof a plurality of messages from a signal transfer point to acorresponding one of a plurality of service control points in accordancewith a weighted distribution plan. The weighted distribution planincludes a respective distribution proportion for each of the pluralityof service control points.

As indicated by block 80, the method includes a step of receiving amessage from a service switching point. As indicated by block 82, themessage is distributed to one of the service control points inaccordance with its respective distribution proportion. The one of theservice control points to which the message is distributed is selectedeither in a deterministic manner, in a stochastic manner, or apseudorandom manner. Thereafter, flow of the routine is directed back toblock 80.

The method acts to distribute a plurality of messages so that eachservice control point receives a proportion of the plurality of messagescommensurate with its respective distribution proportion. In addition,the plurality of messages can be either deterministically distributed orstochastically distributed to produce each respective distributionproportion.

Table IV shows an example of a weighted distribution plan for theportion of the telecommunication system illustrated in FIG. 1. In thisexample, of the messages received by a signal transfer point, 15% (onaverage) are routed to the service control point 20, 35% (on average)are routed to the service control point 22, 35% (on average) are routedto the service control point 24, and 15% (on average) are routed to theservice control point 26. When a service control point is determined tobe malfunctioning, its respective distribution proportion is reduced independence upon the severity of the condition of the service controlpoint. For a catastrophic failure of the service control point, thedistribution proportion is set to zero.

                  TABLE IV                                                        ______________________________________                                                        DISTRIBUTION                                                  SERVICE CONTROL POINT                                                                         PROPORTION   OCCUPANCY                                        ______________________________________                                        SCP1            15%          47%                                              SCP2            35%          60%                                              SCP3            35%          60%                                              SCP4            15%          47%                                              ______________________________________                                    

Although the above-described distribution plans have been presented interms of four service control points, it is noted that distributionplans can be formulated for any number of service control points. Forexample, a cluster of eight service control points can be utilized, eachof which running at 70% occupancy during a peak usage period. Should oneof the eight service control points fail, the remaining seven servicecontrol points pick up the extra load. As a result, the load on each ofthe remaining seven service control points is increased to 80%occupancy.

In general, it is preferred that the occupancy be between 40% and 80%for each of the service control points in a cluster. More preferably,the occupancy of each of the service control points in a cluster isgreater than 50% during a peak usage period.

It is noted that the above-described methods can be performed by or withthe assistance of a processor included with the signal transfer point.The processor is directed by software in the form of computer-readabledata stored by a computer-readable storage medium to perform the stepsof the above-described methods.

Thus, there has been described herein several embodiments includingpreferred embodiments of methods and systems for distributing messagesfrom a signal transfer point to a plurality of service control points.

Because the various embodiments of the present invention regularlydistribute messages among a cluster of service control points, theyprovide a significant improvement in that the service control points canbe utilized with a higher occupancy level than for a mated pairconfiguration. As a result, a fuller utilization of service controlpoint resources is realized without compromising quality of serviceshould one of the service control points fail.

Additionally, the various embodiments of the present invention asherein-described provide distribution plans which are suited for acluster of service control points having either equal or unequalprocessing capacities.

It will be apparent to those skilled in the art that the disclosedinvention may be modified in numerous ways and may assume manyembodiments other than the preferred form specifically set out anddescribed above.

Accordingly, it is intended by the appended claims to cover allmodifications of the invention which fall within the true spirit andscope of the invention.

What is claimed is:
 1. A method of distributing a plurality of messagesfrom a signal transfer point to a plurality of service control points,the method comprising:(a) distributing each of the plurality of messagesfrom the signal transfer point to a corresponding one of the pluralityof service control points in accordance with a distribution plan fordistributing the plurality of messages among the plurality of servicecontrol points, each of the plurality of service control points beingincluded in the distribution plan; (b) determining that one of theplurality of service control points is malfunctioning; and (c) utilizinga modified distribution plan for distributing subsequent messages to theplurality of service control points.
 2. The method of claim 1 furthercomprising:(d) generating an alarm condition in response to themalfunction determined in (b).
 3. The method of claim 1, wherein (b)comprises determining that one of the plurality of service controlpoints is malfunctioning based upon a message received from one of theplurality of service control points.
 4. The method of claim 3, whereinthe message indicates the severity of the malfunction.
 5. The method ofclaim 1, wherein (b) comprises determining that one of the plurality ofservice control points is malfunctioning based upon a duration betweentransferring a query message thereto and receiving a response messagetherefrom.
 6. The method of claim 1, wherein (c) comprises omitting theservice control point determined in (b) to be malfunctioning.
 7. Themethod of claim 1, wherein (c) comprises reducing the share of messagesdistributed to the service control point determined in (b) to bemalfunctioning.
 8. The method of claim 1, wherein (c) comprises reducingthe share of messages distributed to the service control pointdetermined in (c) to be malfunctioning to zero.
 9. The method of claim1, wherein the occupancy of the plurality of service control points isgreater than 50% during a peak usage period.
 10. A signal transfer pointoperative to distribute a plurality of messages to a plurality ofservice control points, each of the plurality of messages beingdistributed to a corresponding one of the plurality of service controlpoints in accordance with a distribution plan including each of theplurality of service control points; and operative to determine that oneof the plurality of service control points is malfunctioning and toutilize a modified distribution plan for distributing subsequentmessages to the plurality of service control points.
 11. The signaltransfer point of claim 10 further operative to determine that one ofthe plurality of service control points is malfunctioning based upon amessage received from one of the plurality of service control points.12. The signal transfer point of claim 10 further operative to determinethat one of the plurality of service control points is malfunctioningbased upon a duration between transferring a query message thereto andreceiving a response message therefrom.
 13. The signal transfer point ofclaim 10 further operative to omit the service control point determinedto be malfunctioning.
 14. The signal transfer point of claim 10 furtheroperative to reduce the share of messages distributed to the servicecontrol point determined to be malfunctioning.